Cis and trans isomers of 1-(5-bromothiophen-2-yl)-3-(10-chloroanthracen-9-yl)prop-2-en-1-one: Synthesis and characterization

Abstract

Chalcone derivatives are simple chemical scaffold found in natural products and have been extensively used as an effective template in medicinal chemistry for drug discovery. Two new geometrical isomers of 1-(5-bromothiophen-2-yl)-3-(10-chloroanthracen-9-yl)prop-2-en-1-one were synthesized, isolated and characterized by various spectroscopic techniques (FT-IR, NMR, LC-MS and UV-visible). Two different shaped (cis and trans) yellow colored single crystals were obtained by slow evaporation method and the molecular structures were confirmed by X-ray diffraction studies. The cis configuration crystallizes in the monoclinic P21/c space group, whereas, trans configuration crystallizes in the orthorhombic P212121 space group. The conformational changes lead to variations in molecular packing arrangement. In cis, 2-D layer-like architecture is constructed by C-H…O and S…S contacts, whereas, in trans 3-D zig-zag pattern is generated by C-H…O, C-H…Cl and Br…π interactions. The unique supramolecular topology of the isomers established by diverse intra and intermolecular interactions was analysed by Hirshfeld surfaces, 2D fingerprint plots, 3D energy framework and NCI index model. The Frontier molecular orbitals explored HOMO-LUMO energy gap and associated electronic properties were calculated. The molecular electrostatic potential (MEP) was plotted to identify the reactive sites in the molecule.